Cannabis Potency

A story appearing in The Australian newspaper that had the headline; ‘Potent marijuana blamed for youth suicides’ once again raises the issues of what do we know about the potency of cannabis in Australia.

There have been many claims made that it is up to 30 times stronger than it used to be but there is no evidence to support this.

Australia has no program for testing cannabis potency and our information comes from police seizures and small independent studies that have produced varying results.

On the evidence available it would appear that the THC content of cannabis has increased a little over the last 20 years but still remain relatively low, under 5%.

However there has been a considerable shift in the form of cannabis used over the past 20 years.

Younger users are now more likely to smoke the flowering heads or ‘buds’ of the plant compared to the leaf. This part of the plant has a greater THC concentration resulting in users taking in larger amounts then in the past.

There is also some evidence to suggest that younger users smoke cannabis through water pipes or ‘bongs’ rather than joints, which are typically used by older users.

They also smoke more, more often.

In this way young people may be exposed to higher levels of THC than older users.